Radial blower

ABSTRACT

A radial blower has an impeller with a radially vaned rim rotatably mounted in a housing adjacent a discharge conduit. The portions of the housing on both sides of the discharge conduit incline outwardly away from the impeller to form wedge-shaped inlet and discharge chambers on both sides of the impeller. The larger ends of the suction and discharge chambers are joined by a return or bypass channel which directs the main portion of flow away from the back into the impeller. The portion of the impeller between the suction and discharge chambers is bordered by a concavely curved flow diverting element having a radius of curvature slightly smaller than the impeller and a maximum distance at its mid-section, which is substantially equal to the radial length of the vanes on the rim of the impeller. An inlet or suction opening in the front wall of the housing is eccentrically disposed relative to the impeller and adjacent the inlet chamber. The inlet conduit is inclined toward the suction chamber. A set of curved deflectors is disposed substantially parallel to each other in the central chamber of the housing within the impeller vanes and substantially in line with the discharge chamber and conduit and having tip ends fairly close to the inner ends of the impeller vanes of the discharge conduit.

United States Patent 1191 Haase RADIAL BLOWER Dietrich E. Haase, 544Mayen, Habsburgring 90, Germany 221 Filed: Nov. 29, 1972 211 Appl. No.:310,473

[76] Inventor:

[30] Foreign Application Priority Data Primary ExaminerC. J. HusarAttorney, Agent, or Firm-Connolly & Hutz [451 Feb. 26, 1974 [57]ABSTRACT A radial blower has an impeller with a radially vaned rimrotatably mounted in a housing adjacent a discharge conduit. Theportions of the housing on both sides of the discharge conduit inclineoutwardly away from the impeller to form wedge-shaped inlet anddischarge chambers on both sides of the impeller. The larger ends of thesuction and discharge chambers are joined by a return or bypass channelwhich directs the main portion of flow away from the back into theimpeller. The portion of the impeller between the suction and dischargechambers is bordered by a concavely curved flow diverting element havinga radius of curvature slightly smaller than the impeller and a maximumdistance at its mid-section, which is substantially equal to the radiallength of the vanes on the rim of the impeller. An inlet or suctionopening in the front wall of the housing is eccentrically disposedrelative to the impeller and adjacent the inlet chamber. The inletconduit is inclined toward the suction chamber. A set of curveddeflectors is disposed substantially parallel to each other in thecentral chamber of the housing within the impeller vanes andsubstantially in line with the discharge chamber and conduit and havingtip ends fairly close to the inner ends of the impeller vanes of thedischarge conduit.

12 Claims, 2 Drawing Figures PATENYED EBZB I974 FIG.2

RADIAL BLOWER BACKGROUND OF THE INVENTION This invention relates to aradial blower wherein the gaseous fluid being pumped is conducted in amultiplicity of passes through a radially vaned impeller.

It is known in the art that relatively high pressures may be produced inradial blowers by utilizing high peripheral speeds (B. Eck, Ventilatoren(Ventilators), 3rd Ed., Berlin 1957, p. 7, equation 11). It is alsoknown in the art that a pair of radial impellers may be mounted on acommon shaft and successively utilized to increase the pressure oneafter the other. In a relatively new type of radial blower described inpublished West German patent application DTOS 1,808,829, the gaseousfluid is circulated in a normal manner about one-half of thecircumference of a radial impeller into an outwardly deviating spiralhousing which returns to the proximity of the impeller in the other halfof the circumference of the impeller, whereby the fluid is recirculatedthrough the impeller blades to increase its pressure.

The peripheral speed of a radial impeller is limited by the physicalstrength of its structural material or by the tolerable sound level. Apair of radial impellers connected in series with careful constructionand arrangement may provide relatively high pressures at a fairly highdegree of efficiency, but require considerable extra parts and increasedexpense. Recirculation of the fluid through a single radial impeller byan arrangement (such as described in published DTOS 1,808,829 having thechamber surrounding the impeller divided into three sections, andparticularly by an outwardly opening spiral, an inwardly closing spiral,and a discharge conduit) makes it possible to obtain a considerableincrease in pressure with a relatively low cost of construction, but itdoes not make it possible to simultaneously favorably influence thepressure and degree of efficiency.

An object of this invention is to control the recirculation of a gaseousfluid through a radial impeller of a blower in such a manner that thepressure and degree of efficiency are significantly increased with'arelatively small increase in the cost of construction in comparison tothat previously described.

SUMMARY OF THE INVENTION In accordance with this invention, theaforementioned object is obtained by bordering the radial impeller onthe side opposite the discharge conduit by a concavely curved flowdiverting element having its concave wall disposed toward the radialimpeller and having a radius of curvature slightly smaller than that ofthe impeller and a maximum'spacing at its mid-section from the impellersubstantially equal to the length of the vanes on the impeller. In otherwords the flowdiverting elements divert flow inwardly between the vanesof the impeller.

This divides the housing about the circumference of the impeller intofour sections, which taken in direction of impeller rotation, include adischarge conduit, a wedge-shaped (or outwardly deviating) inlet chambersubstituted for the aforementioned outwardly opening spiral, aconcavo-convex flow diverting baffle disposed opposite the dischargeconduit, and a wedge-shaped (or inwardly deviating) discharge chambersubstituted for the inwardly developing spiral. The larger ends of theinlet and discharge chambers are connected by a return or bypass channelwhose configuration determines the desired amount of increase inpressure to be obtained from the blower.

This invention has the advantage of at a relatively small structuralexpense with a single radial impeller having a relatively smallthroughput providing higher pressures which otherwise would require twosuccessive radial impeller stages. Another particularly helpfuladvantage is in that the speed of rotation is decreased, which minimizesthe strength of the required construction materials, which is importantfor example when synthetics or plastics are utilized. The relatively lowperipheral speeds also helpfully reduces the sound levels.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERREDEMBODIMENTS In FIGS. 1 and 2 is shown a radial blower having a radialimpeller 1 with an annular array of radial vanes 15 rotatably mountedbetween flat front housing wall 2 and rear housing wall 3. Impellervanes 15 are slightly curved and swept outwardly forward in thedirection of rotation. The portion of the housing disposed betweenimpeller vanes 15 is designated for convenience as a central chamber.The portion of vaned rim 16 of impeller l disposed adjacent suctionopening 5 in front wall 2 is bordered by inlet chamber 6 which deviatesgradually outwardly away from impeller l in the direction of rotationaway from discharge conduit 10 into a wedge shape. Inlet chamber 6 isconnected by return or bypass channel 9 with inwardly deviating orwedge-shaped chamber 8 disposed on the opposite side of dischargeconduit 10 from inlet chamber 6. The opposite side of impeller 1 fromdischarge conduit 10 is bordered by the concavely curved side ofconcave-convex flow diverting baffle 7 having a concave radius ofcurvature substantially equal to the average radius of curvature ofvaned rim 16. The maximum spacing between the midsection of concave wallof element 7 is substantially equal to the radial length of vanes 15 onvaned rim 16. An array of substantially parallel curved deflector vanes11, 12 and 13 is mounted in the central chamber adjacent dischargeconduit 10 and has tip ends disposed near the inner ends of the impellervanes 15. The vanes 11, 12 and 13 are attached to the front wall 2 andproject inwardly therefrom. Deflector vanes 1 1, 12 and 13 are disposedsubstantially parallel to the average line of flow through dischargechamber 8 and discharge conduit 10 and extend substantially adjacent theinner periphery of vaned rim l6. Curved deflector vane 11, having thelargest radius of curvature and length, is

thus disposed substantially tangent to an angle bisecting the portion ofimpeller 1 bordered by exhaust conduit l0.

Suction conduit 4, connected in series with suction opening 5, isinclined with respect to the axis of rotation of impeller l and towardthe area of impeller l bordered by inlet chamber 6. Suction conduit 4also may have attached to its outer end (in a manner not shown) an inletelbow conduit having an end remote from illustrated conduit 4, whoseaxis is disposed substantially parallel to the axis of rotation ofimpeller l.

A radial blower of this invention as described herein has achieved anoutput of over 50 percent, a pressure number (of performance) of 2.4 andyield numbers (of performance) of less than 0.1 referring to thecircular surfaces of radial impeller 1. These definitions are describedand discussed in a publication entitled Ventilatoren (Ventilators) by B.Eck, published in Berlin, Germany, in 1967.

The principal portion of the fluid passing through the radial blower ofthis invention passes from suction conduit 4 into the central portion ofradial impeller 1 and from there into inlet chamber 6. This principalportion is then subsequently passed through return or bypass channel 9into inwardly deviating discharge chamber 8 and then after again passingthrough impeller 1 flows into discharge conduit 10. Some of the impelledgaseous fluid passes from suction conduit 4 into the concave chamberbordered by flow diverting element 7 in which a return flow occurstoward the central chamber disposed within the radial impeller. Theportion of the gaseous fluid from which this reversal of flow occurs ifsplit by nozzle suction 14 which is disposed closely adjacent impeller 1at the beginning of inlet chamber 6 in such a manner that one portionflows directly into discharge conduit 10 and the other flows into thenarrow entrance to inlet chamber 6. This reduces the speed of flow inthe portion of discharge conduit 10 adjacent nozzle 14 relative to theaverage speed of flow through discharge conduit 10, which materiallyreduces the noise produced by the blower. On the other hand, the speedof flow in inlet chamber 6 otherwise increases which reduces flow lossesin channel 9.

The structure of the radial blower is highly simplified by constructingit within a casing having an over-all elliptical cross-section withimpeller 1 and discharge conduit 10 at one end and return or bypasschannel 9 at the other end. Bypass or return channel 9 is constituted byarcuately pointed concavo-convex baffle 7 whose concavely curved sideborders the periphery of impeller 1 which is disposed opposite dischargeconduit 10. The convexly curved side of baffle 7 forms the inner wall ofreturn channel 9.

I claim:

1. A radial blower comprising a housing having a curved periphery, animpeller having a radially vaned rim, shaft and bearing means rotatablymounting said impeller within said housing, said housing also having afront wall disposed adjacent a vaned side of said impeller, a suctionopening in said front wall eccentrically disposed relative to saidimpeller, a discharge conduit in the portion of said periphery near saidsuction opening, the portion of said peripheryin the direction ofrotation of said impeller away from said discharge conduit deviatingoutwardly from a nozzle section disposed substantially adjacent to saidimpeller at said discharge conduit into a wedge-shaped inlet pressurechamber of increasing cross-sectional area, the portion of saidperiphery on the side of said discharge conduit opposite to said nozzleapproaching inwardly toward said impel ler in the direction of rotationof said impeller to form a wedge-shaped discharge chamber, a curvedreturn channel connecting the wider ends of said inlet and dischargechambers for conducting the main portion of pumped fluid from said inletchamber to said discharge chamber whereby it is directed back into saidimpeller, the portion of said impeller disposed opposite said dischargeconduit and between said suction and discharge chambers having aconcavely curved bordering element disposed adjacent said impeller andbridging the portion of said impeller disposed between said inlet anddischarge chambers and said return channel, and said concavely curvedbordering element having a curvature constructed and arranged to divertflow between it and said impeller inwardly between said vanes of saidimpeller.

2. A radial blower as set forth in claim 1 wherein said concavely curvedbordering element has a radius of curvature slightly smaller than theradius of curvature of said impeller.

3. A radial blower as set forth in claim 2 wherein said concavely curvedbordering element has a midsectional maximum spacing from said impellersubstantially similar to the radial length of said vanes.

4. A radial blower as set forth in claim 1 wherein the.

portion of said housing within said vanes comprises a central chamber,deflector vanes projecting from said front wall and being. disposed insaid central chamber substantially parallel to the line of flow throughsaid discharge chamber and said discharge conduit whereby fluid currentscirculating within said central chamber are directed into said dischargeconduit.

5. A radial blower as set forth in claim 1 wherein said impeller vanesand said deflector vanes have portions adjacent said discharge conduitdisposed near to each other.

6. A radial blower as set forth in claim 4 wherein said deflector vanesare slightly curved.

7. A radial blower as set forth in claim 6 wherein said deflector vanesare disposed substantially parallel to each other and have substantiallysimilar radii of curvature.

8. A radial blower as set forth in claim 1 wherein a suction conduit isconnected to said suction opening on said front wall of said housing andsaid suction conduit being inclined toward said inlet chamber whereby itdirects suction fluid into said inlet chamber.

9. A radial blower as set forth in claim 8 wherein a curved elbowsection is connected to said inclined suction conduit, and said curvedelbow section has a portion remote from said inclined section which isdisposed substantially parallel to the axis of rotation of saidimpeller.

10. A radial blower as set forth in claim 1 wherein said housingcomprises a substantially elliptical outer casing, said impeller beingdisposed at one end of said elliptical casing, said return channel beingdisposed at the other end of said elliptical outer casing, and saidconcavely curved bordering wall and the'inside wall of said returnconduit comprising a concavoconvex baffle disposed within said casingwith its concave wall facing said impeller.

11. A radial blower as set forth in claim 1 wherein said vanes areslightly curved.

12. A radial blower as set forth in claim 11 wherein said vanes slightlycurve outwardly forward.

1. A radial blower comprising a housing having a curved periphery, animpeller having a radially vaned rim, shaft and bearing means rotatablymounting said impeller within said housing, said housing also having afront wall disposed adjacent a vaned side of said impeller, a suctionopening in said front wall eccentrically disposed relative to saidimpeller, a discharge conduit in the portion of said periphery near saidsuction opening, the portion of said periphery in the direction ofrotation of said impeller away from said discharge conduit deviatingoutwardly from a nozzle section disposed substantially adjacent to saidimpeller at said discharge conduit into a wedgeshaped inlet pressurechamber of increasing cross-sectional area, the portion of saidperiphery on the side of said discharge conduit opposite to said nozzleapproaching inwardly Toward said impeller in the direction of rotationof said impeller to form a wedge-shaped discharge chamber, a curvedreturn channel connecting the wider ends of said inlet and dischargechambers for conducting the main portion of pumped fluid from said inletchamber to said discharge chamber whereby it is directed back into saidimpeller, the portion of said impeller disposed opposite said dischargeconduit and between said suction and discharge chambers having aconcavely curved bordering element disposed adjacent said impeller andbridging the portion of said impeller disposed between said inlet anddischarge chambers and said return channel, and said concavely curvedbordering element having a curvature constructed and arranged to divertflow between it and said impeller inwardly between said vanes of saidimpeller.
 2. A radial blower as set forth in claim 1 wherein saidconcavely curved bordering element has a radius of curvature slightlysmaller than the radius of curvature of said impeller.
 3. A radialblower as set forth in claim 2 wherein said concavely curved borderingelement has a mid-sectional maximum spacing from said impellersubstantially similar to the radial length of said vanes.
 4. A radialblower as set forth in claim 1 wherein the portion of said housingwithin said vanes comprises a central chamber, deflector vanesprojecting from said front wall and being disposed in said centralchamber substantially parallel to the line of flow through saiddischarge chamber and said discharge conduit whereby fluid currentscirculating within said central chamber are directed into said dischargeconduit.
 5. A radial blower as set forth in claim 1 wherein saidimpeller vanes and said deflector vanes have portions adjacent saiddischarge conduit disposed near to each other.
 6. A radial blower as setforth in claim 4 wherein said deflector vanes are slightly curved.
 7. Aradial blower as set forth in claim 6 wherein said deflector vanes aredisposed substantially parallel to each other and have substantiallysimilar radii of curvature.
 8. A radial blower as set forth in claim 1wherein a suction conduit is connected to said suction opening on saidfront wall of said housing and said suction conduit being inclinedtoward said inlet chamber whereby it directs suction fluid into saidinlet chamber.
 9. A radial blower as set forth in claim 8 wherein acurved elbow section is connected to said inclined suction conduit, andsaid curved elbow section has a portion remote from said inclinedsection which is disposed substantially parallel to the axis of rotationof said impeller.
 10. A radial blower as set forth in claim 1 whereinsaid housing comprises a substantially elliptical outer casing, saidimpeller being disposed at one end of said elliptical casing, saidreturn channel being disposed at the other end of said elliptical outercasing, and said concavely curved bordering wall and the inside wall ofsaid return conduit comprising a concavoconvex baffle disposed withinsaid casing with its concave wall facing said impeller.
 11. A radialblower as set forth in claim 1 wherein said vanes are slightly curved.12. A radial blower as set forth in claim 11 wherein said vanes slightlycurve outwardly forward.